Bellows valve

ABSTRACT

A valve including a bonnet mounted on a body and having an actuator carried in a central passage in the bonnet. The body includes a fluid passageway connecting an inlet and an outlet, an annular sealing seat in the passageway and a bore intersecting the passageway substantially coaxially with said seat. The central passage in the bonnet is aligned substantially coaxially with the bore in the body, and the inner end of the actuator is connected to a non-rotatable stem which is reciprocated by the actuator into and out of sealing engagement with the seat. The connection between the stem and the actuator comprises a cup on the lower end of the actuator into which the upper end of the stem projects, and a groove around the periphery of the upper end of the stem into which a pair of detents project from the wall of the cup. Thereby the stem and actuator are locked together for coordinated axial movement while allowing relative rotational movement. The cup and the upper end of the stem present opposed, substantially cone-shaped surfaces for abutting a friction reducing ball held therebetween. The ball minimizes the amount of torque transmitted from the rotatable actuator to the nonrotatable stem. The lower end of the stem carries sealing means for co-acting with the valve seat and includes a plug mounted within a polygonal body having a plurality of rounded guiding corners for engaging the bore wall. A bellows surrounds a portion of the stem with its lower end bonded to the stem and its upper end bonded to a weld ring. The weld ring is sealingly clamped between the body and the bonnet. Concentric grooves are formed in the weld ring with at least one of the grooves opening upwardly toward a flat face on the lower end of the bonnet. The upwardly opening groove contains an O-ring sealingly compressed between the flat face of the bonnet and the bottom of the groove. Another groove is sufficiently close to an edge of the weld ring as to form an upstanding flange of radial thickness not substantially greater than the thickness of the bellows. An outwardly flaring surface merges with the terminus of the bonnet passage and its maximum diameter is greater than the diameter of the crest of the flange which is bonded to said bellows.

United States Patent [1 1 Shufflebarger et al.

[ Jan. 22, 1974 1 BELLOWS VALVE [75] Inventors: Earl D. Shufflebarger;Bernard J. Gallagher, both of Mentor; David M. Simko, Parma Heights;John R. Boylan, Cleveland Heights, all of Ohio [73] Assignee: NuproCompany, Cleveland, Ohio [22] Filed: Aug. 5, 1971 [21] Appl. No.:169,316

[52] US. Cl 251/335 B [51] Int. Cl. Fl6k 41/04 [58] Field of Search251/335 B, 81, 77, 86, 87

[56] References Cited UNITED STATES PATENTS 2,740,425 4/1956 Garland251/86 X 2,848,187 8/1958 Henry 251/86 UX 2,881,602 4/1959 Baker et al.251/81 X 3,105,518 10/1963 Kunz 251/77 X 3,528,087 9/1970 Perkins251/335 B 2,682,386 6/1954 Lindsay 251/335 B 2,114,139 4/1938Crosthwait, Jr. et al 251/335 B 2,308,183 l/l943 Lewis et al. 251/335 B2,524,730 10/1950 Lawhon 251/335 B 3,510,100 5/1970 Makusay et al 251/86X 3,625,474 12/197] .luede 251/335 B Primary Examinersamuel ScottAttorney, Agent, or FirmFay, Sharpe and Mulholland [57] ABSTRACT A valveincluding a bonnet mounted on a body and having an actuator carried in acentral passage in the bonnet. The bodyincludes a fluid passagewayconnecting an inlet and an outlet, an annular sealing seat in thepassageway and a bore intersecting the passageway substantiallycoaxially with said seat. The central passage in the bonnet is alignedsubstantially coaxially with the bore in the body, and the inner end ofthe actuator is connected to a non-rotatable stem which is reciprocatedby the actuator into and out of sealing engagement with the seat. Theconnection between the stem and the actuator comprises a cup on thelower end of the actuator into which the upper end of the sternprojects, and a groove around the periphery of the upper end of thestern into which a pair of detents project from the wall of the cup.Thereby the stern and actuator are locked together for coordinated axialmovement while allowing relative rotational movement. The cup and theupper end of the stem present opposed, substantially cone-shapedsurfaces for abutting a friction reducing ball held therebetween. Theball minimizes the amount of torque transmitted from the rotatableactuator to the nonrotatable stem. The lower end of the stem carriessealing means for co-acting with the valve seat and includes a plugmounted within a polygonal body having a plurality of rounded guidingcorners for engaging the bore wall. A bellows surrounds a portion of thestem with its lower end bonded to the stem and its upper end bonded to aweld ring. The weld ring is sealingly clamped between the body and thebonnet. Concentric grooves are formed in the weld ring with at least oneof the grooves opening upwardly toward a flat face on the lower end ofthe bonnet. The upwardly opening groove contains an O-ring sealinglycompressed between the flat face of the bonnet and the bottom of thegroove. Another groove is sufficiently close to an edge of the weld ringas to form an upstanding flange of radial thickness not substantiallygreater than the thickness of the bellows. An outwardly flaring surfacemerges with the terminus of the bonnet passage and its maximum diameteris greater than the diameter of the crest of the flange which is bondedto said bellows.

22 Claims, 9 Drawing Figures ATENTED JAN 2 21974 SHEET 1 BF 2 vINVENTOR. EARL D. SHUFFLEBARGER BERNARD J. GALLAGHER BY DAVID M. SIMKOJOHN R. BOYLAN ,164,, 5 g macaw ATTORNEYS PATENTEU 3, 787. 023

sum 2 or 2 INVENTOR. EARL D. SHUFFLEBARGER BERNARD J. GALLAGHER BY DAVIDM. SIMKO 36' FIG 9 JOHN R. BOYLAN ay, 5W Z Mal/10M ATTORNEYS BELLOWSVALVE BACKGROUND OF THE INVENTION This is an improvement of theinvention shown and described in U.S. Pat. Nos. 3,278,156; 3,428,291 and3,491,789. It is similarly applicable to cryogenic, high temperature,vacuum and high pressure environments.

Common features in the valve of this application and the valve shown inU.S. Pat. No. 3,491,789 to Callahan et al. include a bonnet clamped to avalve body by a union nut, an actuator projecting into a central passagein the bonnet, a stem connected to the lower end of the actuator andprojecting through a bore into a flow passage in the body, a tip on thelower end of the stern for sealingly engaging a seat in the flow passageand a bellows surrounding a portion of the stern.

One improvement provided by the valve of this invention includes anelongated threaded connection between the stem and the bonnet having anL/D ratio of approximately 1.5:1 (where L is the thread length and D isthe thread diameter). The increased L/D ratio provides better guidingfor the stem and minimizes thread stripping. The requirement of improvedguiding and higher strength threads is necessitated by the handling ofhigher pressures in the valve.

Two diametrically opposed apertures are formed in the bonnet below thethreaded bonnet-stem connection and above a back seat. Cooling andheating fluid may be passed through one of the apertures into the bonnetand out through the other aperture. Alternatively, one aperture could beplugged and a sensor could be provided in the other aperture for leakdetection. The provision of a back seat below the sensor or coolingapertures minimizes contamination of cooling fluid passing through thevalve should the bellows leak. This is an improvement over the structureof the valve shown in the Callahan et al. U.S. Pat. No. 3,491,789 wherethe back seat for minimizing gross leakage is located above the coolingapertures.

The connection between the actuator and the stem is particularly aproblem in valves where extremely high pressures or extremely lowpressures with diverse temperature changes of large magnitude areencountered. Two pins are provided by this invention which projectthrough the walls of the cup-shaped end of the actuator and through asemicircular groove in the upper end of the stem. The pins are locatedin diametrically opposed positions. Thereby, when the stem tends tostick or adhere to the valve seat the two pins will engage the groovewalls as the actuator is retracted and induce dual vertical forces onthe stem. This balanced upward force application prevents canting of thestem as sometimes is the case when a single pin is used such as is shownin the structure of U.S. Pat. No. 3,491,789.

The shape of the groove in the stem has been improved from a flat sidedtrough as shown in the Callahan et al. patent to a semicircular shapedgroove with chrome plated wear surfaces. The chrome plating minimizesfriction and also hardens the surface to minimize wear. The groove inthe stem structure of the Callahan et al. patent allows maximum radialdistortion at the groove section during compression; the bottom of thegroove being the minimum section of the stem. It is also the sectionwhere the maximum radial bulge results during compression which tends todislocate the locking pin. With the semicircularshaped groove of thisinvention, radial pin displacement is not so much of a problem.

A weld ring is clamped between the bonnet and the body and a groove inthe upper surface of the weld ring contains a hollow metal O-ring whichseals against a planar surface of the bonnet. The bellows structure iswelded to the inner periphery of the weld ring which in some casesresults in a raised weld bead projecting above the ring toward thebonnet. To prevent the bonnet from engaging the weld bead it is flaredat its lower end and the planar surface has a minimum inside radiuswhich is greater than the maximum weld bead outside radius.

In the valve design of this invention the bellows structure is welded toa flange on the stem and extends upwardly to the weld ring where it isagain welded. This configuration of the bellows structure is a departurefrom the Callahan et al. patent structure and represents a substantialimprovement. With the Callahan et al. patent structure fluid contactsthe interior of the bellows. In the valve of this application fluidcontacts the exterior of the bellows. When compared to the bellowsstructure of the Callhan U.S. Pat. No. 3,491,789, the bellows of thisinvention may be said to be inverted. The inverted bellows design offersmany advantages.

When a fluid system must be purged the bellows structure of thisinvention allows for much easier cleaning when the valve is disassembledbecause the fluid contact area of the bellows is at the exterior ratherthan the interior of the structure. In addition, system pressure acts onthe outside of the bellows, rather than the inside. This is verydesirable in larger bellows valves because it reduces the possibility ofthe bellows slinking and results in longer cycle life. Also this designis recommended for applications such as liquid metal, where the systemfluid must be heated to flowing conditions prior to operating the valve.Since the system fluid is in contact with the body of the valve in thebellows area maximum heat transfer is possible.

The lower end of the stem includes a coaxially mounted stem tip. The tipconsists of a polygonal body connected to the stem and a plug or insertmember crimped into a cavity formed in the lower face of the body. Aplurality of flow passages about the body llows for evacuation of thevalve for vacuum service. In addition, the body provides a plurality ofrounded corners for centering and guiding the stem within the valve bodybore. The plug, ordinarily of a different material than the body, ispress fitted into the cavity of the body and is compressed against thebottom of the cavity by crimping. This operation is performed prior tothe assembly of the tip with the stem. Crimping of vthe plug tends tominimize the migration of fluid behind the plug which could in somecases cause the plug to blowout of the cavity when there is a suddenchange in pressure. In addition, crimping procedures a minimum of deadspace in the cavity which reduces contamination when the system ischanged from one fluid to another.

BRIEF DESCRIPTION OF THE INVENTION The valve of this invention includesa bonnet connected to a body by a union nut. The body includes an inletand an outlet connected by a flow passage with an intermediate annularsealing seat surrounding the flow passage. A reciprocable, non-rotatingstem projects through a bore in the body and is adapted to seal againstthe seat, the stem being coaxially aligned with both the seat and thebore.

A portion of the stem within the bore is surrounded by a bellowsstructure. The lower end of the bellows structure is bonded to the stemand its upper end is bonded to a weld ring. The weld ring is in turnclamped between the upper end of the body and the lower end of thebonnet thus restricting fluid to a space in the body which is exteriorof the bellows.

The upper end of the stem includes a semicircular shaped groove formedin its periphery. The stem projects into a cup-shaped portion on thelower end of an actuator. The actuator extends upwardly from the stemthrough a central passage in the bonnet. Two pins project through theside walls of the cup-shaped portion of the actuator and lock the stemand actuator together.

The opposed end faces of the stem and cup-shaped cavity include concaveconical surfaces which hold a polished ball for minimizing both frictionand the transmission of rotational forces from the actuator to the stem.

A particularly long thread is provided on the actuator to engage matingthreads on the interior of the bonnet. The increased thread lengthprovides a guide for the actuator to assist in centering the stem withinthe bore and to minimize thread stripping at high pressure.

Near the lower terminus of the central passage of the bonnet is anoutwardly flaring frusto-conical surface particularly designed such thatthe lower end of the bonnect contacts only a portion of the weld ringconnected to the upper end of the bellows. The weld ring includes twoupwardly facing grooves with the outermost groove containing a O-ringwhich seals a lower flat face of the bonnet and the bottom of itsgroove. The second or innermost groove is formed to provide an upwardlyextending flange near the inner periphery of the ring which is notsubstantially thicker than the bellows. If the flange were substantiallythicker than the bellows it would act as a heat sink during the weldingprocess and inhibit the formation of a weld bead.

Often welding produces a weld bead which projects above the originalsurface of the weld ring; Such a projection of the bead could preventsealing between the O-ring and the bonnet. To alleviate this potentialproblem the flared surface at the lower end of the bonnet has a minimuminside diameter which is greater than the maximum outside diameter ofthe crest of the flange at the inner edge of the weld ring. Thus, thebonnet cannot contact the weld bead.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view, partlyin phantom, of the preferred embodiment of the valve of this invention;

FIG. 2 is an enlarged elevational view, partly in section, of a portionof the preferred embodiment of the valve of this invention;

FIG. 3 is a sectional view of the bellows and weld ring of the valve ofthis invention;

FIG. 4 is a sectional view taken along line 4-4 of FIG. 2;

FIG. 5 is an enlarged fragmentary sectional view of the stem tip of thisinvention;

FIG. 6 is an enlarged fragmentary view of the connection between thestem and actuator of the valve of this invention, partly in section;

FIG. '7 is an enlarged fragmentary sectional view of the preferredembodiment of the connections between the bellows and the stem, thebellows and the weld ring, and the bonnet, weld ring and body;

FIG. 8 is a sectional view of a modification of the joint between thebonnet, weld ring and body using ring sealing; and

FIG. 9 is a sectional view of a further modification of the jointbetween the bellows and the weld ring.

PREFERRED EMBODIMENT Referring to FIGS. 1 and 2, the valve 10 includes abody 12 joined to an elongated bonnet 14 by a union nut 16. An actuator18 projects upwardly from the bonnet and a handle 20 is attached to itsouter end. A packing nut 22. is threadably received over the upper endof the bonnet 14 to hold packing 26 in compression against actuator 18.A jam nut 24 locks the packing nut 22 in place to prevent accidentalloosening and relaxation of the compression on the packing 26.

Packing 26, in the preferred embodiment, is made up of a three pieceTeflon or asbestos-Inconel packing system fully contained by metalcomponents on all sides. This packing system provides back-up sealingover the primary bellows seal to be described below.

The body 12 is provided with an inlet 30 and an outlet 32 connected by afluid flow passageway 34. A bore 36 intersects the passageway 34. Valveseat 38 is defined by body 12 intermediate the inlet and outlet.

Coaxially disposed within the bore 36 is a stem 40. An aperture 44 (FIG.7) at the lower end of the stem receives a stem tip 46 in threadedengagement. The tip includes a body 48 having a polygonal cross-sectionand a plug or insert 54 held within the body. Preferably the body 48 ismachined from a hexagonal piece of bar stock but, the word polygonal asused herein is intended to define any body having aplurality of sidesgreater than two. Rounded corners 50 are provided on the body 48 whichis only slightly smaller in diameter than the bore 36. The corners 50provide six sliding surfaces for guiding the tip and keeping it centeredin the bore while at the same time providing six flow passages about thebody for evacuating fluid from the valve. If desired, the guide surfacesmay be chrome plated. A cavity 52 is formed in the lower end of the body48. Prior to assembly of the body with the stem, the plug 54 is pressfitted into the cavity and subsequently crimped into place.

As to a choice of materials, it is preferred that the body 48 bestainless steel (type 316) and the lug be KEL-F or STELLITE. The twodifferent plug materials give a wide variety of useful applications.During operation of the valve the tip 46 must take several forcesincluding torsion, compression, etc. and it is preferred that the body48 be made of a different material than the plug 54. However, it ispossible that the plug and body could be machined as a single element orthe tip could be machined directly on the lower end of the stem.Clearly, replaceable tips 46 allow a wider variety of uses for the valvethan if the tip were made integral with the stem.

In the case of a STELLITE plug 54, a groove 56 is preformed therein asit is a particularly hard material. The plug is press fitted into thecavity 52 and an inwardly extending rib 58 is crimped into the sidewall60 of the body 48. Note particularly in FIG. 5 that the inner surface ofthe rib 58 engages the groove 56 in a manner to put the upper portion ofthe plug 54 in compression against the cavity wall. Thus, the plug willsubstantially fill the cavity and minimize vertical play, therebyminimizing the possibility of migration of fluid behind the plug.

Where the plug material is KEL-F the outer surface is formed in acylindrical shape and the deformation of the sidewall 60 (forming therib 58) forms a groove 56 in the softer KEL-F material by cold flow. TheKEL-F is placed in compression against the cavity wall for the samereason as outlined above with respect to the STELLITE plug.

A bellows 61 is bonded at one end to a ridge 62 (FIG. 7) projectingradially outwardly from the stem 40. The ridge 62 has a groove 64 formedin its lower surface to define a flange 66 not substantially thickerthan the bellows 61. The purpose of the flange 66 will be explainedbelow.

The bellows extends substantially to the upper terminus of the bore 36where it is joined to a weld ring 67. The weld ring 67 includes twocircumferential grooves 68, 74 cut in its upper face. The outermostgroove 68 contains a hollow metal O-ring 70. In the preferred embodimentthe O-ring material is silverplated Iconel-X. The union nut 16, whichengages a flange 73 on the bonnet 14, clamps the lower flat surface 72of the bonnet in sealing engagement with the O-ring 70. The innermostgroove 74 is cut sufficiently near the inner periphery of the weld ringas to provide an upstanding flange 76 not substantially thicker than thebellows 61. Preferably at its crest 78 the flange 76 is approximately inthe range 2 3 9% times the thickness of the bellows 61. Similarthickness ranges are provided by flange 66 on the ridge 62.

The reason for the criticality of the thickness of flanges 76 and 66 isthat the mass of the ring or ridge being welded to the bellows 61 is somuch greater than the mass of the bellows itself that the ring or ridgeacts as a heat sink. Where the crest width is substantially greater thanthe bellows width, the flange will not be heated to welding temperatureat the same time as the bellows. Unless the dimensional relationshipjust described is maintained, the bellows may melt while the ring orridge is being heated with the result that a sound weld will not beformed.

The stem 40 is generally cylindrical in configuration and is slightlysmaller in diameter than the inside diameter of the bellows 61.Additionally, the bellows is only slightly smaller in diameter than thebore 36. These close dimensional relationships provide a certain amountof guiding and aligning for the stem tip 46. Stainless steel (300series) is the preferred bellows material. lnconel or other alloys mayalso be used. Any compatible materials may be used for the stem 40 andthe weld ring 67.

The bonnet 14 is provided with a central passage 80 into which the upperend of the stem 40 projects. The central passage 80 is coaxially alignedwith the stem 40 and the bore 36 and a flared frusto-conical surface 82is provided at its lower terminus. As best illustrated in FIGS. 7 and 8,the flared surface 82 has its largest diameter at the lower flat surface72 and is large enough that it will clear the crest 78 of the flange 76on the weld ring. Thus there is no possibility of direct engagement ofthe bonnet with the weld bead 84. Such engagement could impair sealingat the O-ring 70.

As an alternate embodiment a step, recess or undercut portion may beprovided at the base of the bonnet so that the bonnet does not engagethe weld bead 84. As used herein the term relieved surface should beconsidered generic to a flared surface or a step, recess or undercutportion.

The actuator 18 is threaded at 86 to interengaging threads on theinterior of the'bonnet. In the preferred embodiment Acme powertransmission threads are used. It is preferable that the ratio of threadlength to thread diamete (L/D) be approximately 1.5 :l or greater. Thisratio provides greater guiding capabilities to keep the actuator 18,stem 40 and seat 38 coaxially aligned. It also provides greaterresistance to high pressure.

The actuator extends downwardly toward the stem 40 and on its lower endincludes a cup-shaped portion 88 with a frusto-conical shoulder 90defined at the juncture of the actuator shank and the cup-shapedportion. The frusto-conical shoulder 90 cooperates with a similarlyconfigured transverse shoulder 92 on the bonnet. Together the shoulders90 and 92 serve as a back seat to prevent gross leakage of hazardousfluids from the valve in case of an accident in which the be]- lows 61may rupture.

The upper end of the stem 40 projects into a recess 94 in the interiorof the cup-shaped portion 88. An annular, semicircular shaped groove 96(FIG. 6) is formed in the upper end'of the stem and loosely receivesdiagonally opposed free floating pins or detents 98 carried by thecup-shaped portion. Preferably, the pins 98 project through apertures inthe sidewall of the cup-shaped portion and may be retracted when it isdesirable to disconnect the actuator 18 from the stem 40. However, it ispossible to connect the stem and actuator by deforming the sidewall ofthe cup-shaped portion after the upper end of the stem has been insertedinto the recess 94. The deformed sidewalls would thus have nipple-likedetents projecting into the groove 96, permanently locking the stem tothe actuator. Removable detents are preferred, however.

The upper end of the stem further includes a conical depression 100 withhe apex of the depression being on the longitudinal axis of the stem 40and aligned with the apex of a similar conical depression 102 formed inthe bottom of the recess 94 in the cup-shaped portion. A ball 104 isinterposed between the upper end of the stem and the bottom of therecess with portions of the ball being received in the conicaldepressions 100 and 102. The ball allows relative rotational movementbetween the stem and the actuator with a minimum of friction. In thepreferred embodiment the ball is a precision ball bearing.

The dimensional relationships between the cupshaped portion 88 of theactuator, the pins 98, the ball 104 and the conical surfaces 100, 102,together with the resilience of the bellows 61 and the fluid pressure inthe system cause the ball 104 to be retained in the recess 100, 102.With the valve in a closed position, the pins 98 are located centrallyof the groove 96 and transmit no torque to the stem 40 during valveactuation. In the event that the stem tip 46 should stick to the seat 38for any reason, upward movement of the actuator 18 will move the pins 98to a position in engagement with the sidewall of the groove 96 therebyexerting a light but positive lifting force on the stem.

Two diagonally opposed pins are preferred because they impose equalvertical lifting forces on diametrically opposed surfaces of the upperwall of the groove 96, whereas, a single pin transmits an unbalancedforce which would tend to cant the stem 40 relative to the bore 36 andmisalign the stem tip 46 with respect to the seat 38.

The groove 96 is provided with a polished chrome plated surface tominimize frictional contact between the pins 98 and the groove andfurther to make a harder surface for minimizing wear. The semicircularshaped groove surface minimizes barrel bulge which is always greatest atthe minimum cross-section of a bar under compression. In this case thestem 40 acts as a bar under compression when the valve is closed. Theprovision of a semicircular shaped groove minimizes the barrel bulgeeffect and tends to minimize the radial deflection of the pins due tosuch a barrel bulge.

To reduce further the possibility of torque transfer to the bellows whenactuating the stem, the ball 104 has a diameter as large as possible.The ball 104 contacts the conical surface 100 in line contact with theline being substantially a circle coaxial with the stem. A similarcondition exists with respect to the conical surface 102. The result isa desirable wide distribution of the load and a consequent reduction inthe unit load thus minimizing the possibility of galling between theball 104 and the conical surfaces 100, 102. As a further precautionagainst galling and wear, the ball 104 and surfaces 100, 102 are highlypolished to a finish of 63 micro inches or better. The ball and allsurfaces in contact with the ball have a hardness of at least 55 on theRockwell C scale. A lubricant may be used to even further reduceundesirable friction.

With respect to the operation of the stem, the shortest possible strokeis the most desirable. There is an inverse relationship between thedegree of flexture of the bellows walls and the useful life of thebellows.

In an exemplary valve the pins connecting the two stem sections areapproximately 0.078 inches in diameter whereas the groove isapproximately O.l25 inches in diameter.

Contrary to the structure of the aforementioned Callahan et al patent,(where the bellows is always operating in tension) the bellows of thevalve of this invention is operating approximately percent in tension(extension) and 80 percent in compression. That is, in operation thereis a null point at which the bellows is at rest. When it is extendedfrom the null point it is in tension. When it is compressed from thenull point it is in compression. The bellows acts somewhat as a springin this relation and will expand or contract naturally as would a springunder similar circumstances.

Because there may be a need for changing the stem tip 46 after thebellows 61 is welded to the stem 40, wrench flats 105 are provided onthe stem above the bellows. This is necessary because the turning ortorquing action necessary to loosen or tighten the tip might result in atwisting of the bellows. Since the bellows may fail in torsion the flats105 provide a gripping surface for a wrench and thus protect the bellowsagainst twisting.

As shown in FIG. 2, the valve may include a pair of opposed apertures106, 108 in the walls of the bonnet 14. A tube stub 110 is received ineach of these apertures and is secured to the bonnet to serve as aconnection element for a fluid line. The tube stub includes a passage incommunication with the interior of the bonnet. By using a pair of stubsthe bonnet design lends itself to a system where either a cryogenic or ahigh temperature medium may be passed through the valve. During hightemperature operation, for instance, a medium could be introducedthrough the stubs 1 10 which would continually dissipate heat allowingfor satisfactory valve operation. Strip heaters have been applied to thebody to minimize heat loss in some applications. During cryogenicservice a cold refrigerant could be passed through the stubs to minimizeheat transfer to the cryogenic fluid.

For most applications of the valve, however, the tube stubs are notnecessary.

The use of a single tube stub is also contemplated. In such applicationsthe stub could be used to pipe fluid back through a reservoir or toactuate an alarm in the event of bellows failure. Another potential usewould be to allow a vacuum to be produced in the bellows duringcryogenic service or, conversely, to permit pressurization of the valvein the bellows to attain higher pressure service. Pressurization outsideor above the bellows equalizes the load on the bellows resulting inincreased cycle life of the bellows.

In high pressure applications, the loading on the stem actuator 18 issubstantial and frequently results in galling of the threads 86. As aresult, the actuation of the valve becomes very difficult. By having adifferent degree of hardness on the actuator threads as compared to thehardness on the bonnet threads the tendency to gall is virtuallyeliminated. Preferably the actuator threads are harder than the matingthreads in the bonnet.

Turning now to the sealing mechanism between the upper end of the body12 and the lower end of the weld ring 67, it may be observed in FIG. 2that the union nut 16 compresses the weld ring 67 between the lower endof the bonnet 14 and the weld ring 67 between the lower end of thebonnet 14 and the upper end of the body 12.

The lower portion of the weld ring 67 is welded at 1 11 directly to thebody 12. The periphery of the body is raised slightly at 114 and thering 67 has a cooperatively shaped recess (thereby providing a slightoffset).

It should be noted that the raised portion 114 on the body is slightlyhigher than the mating recess in the weld ring thereby preventing thering from bottoming prematurely and thus leaving a relatively large gapto be filled by weld material 111. The raised portion 114 is preferably0.020 inches higher than the cooperating recess in the weld ring.

In the preferred embodiment the bellows to stem, bellows to ring, andbellows assembly to body connection are Hell-arc welded providing an allmetal, hermetically sealed valve. The bellows assembly can also besealed to the body using a weld ring of the type shown in FIG. 7 and asolid metal O-ring as will be described below.

If desired, a bonnet port 112 may be formed in the union nut 16 by meansof which the integrity of the primary seal between the body, bonnet andring may be tested by helium leak test procedures.

FIG. 8 shows a seal structure at the weld ring where it is desired toeliminate the weld at the body. In this embodiment (which is preferredwhen a weld is not used) a solid metal O-ring 118 is placed between thelower face of the weld ring 67 and the-upper face of the body to providesealing. It should be noted that the weld ring 67 of FIG. 8 isessentially the same as the weld ring of FIG. 7. The only difference isthat O-ring 118 of FIG. 8 is substituted for weld 1 1 l of FIG. 7. Thecooperating rise and recess permit the weld ring to be usedinterchangeably without appreciably affecting the bellows stroke.

FIG. 9 shows an alternate weld ring structure and an alternateweld-ring-beelows joint structure. The valve body is provided with arelieved surface or flare 123 near the upper terminus of the bore 36.Only a single groove 124 is formed on the upper face of the weld ring120. A second groove 126 is formed near the ring lower surface toprovide a flange 128 having a crest suitable for welding to theperiphery of the bellows 122.

Other designs and modifications of the weld ring and the joint betweenthe bonnet and the valve body may be obvious to those having ordinaryskill in the art and such are within the contemplation of thisinvention. This invention should not be considered limited to anyparticular design of the weld ring itself.

As has previously been noted the bellows of the preferred embodimentoperates 20 percent in tension (extension) and 80 percent incompression. Stated in other words the bellows is flexed 20 percentbeyond the free state position when the valve is closed. It iscompressed 80 percent beyond the free state position when the valve isopened. The pins 98 come into operation to engage the walls of groove 96as the valve is opened to positively pull the bellows and stem upwardlybeyond the null point of the bellows to place the bellows incompression. In prior art valves of the type shown in the Callahanpatent the bellows is compressed beyond the free state position when thevalve is closed. It is not extended, however, beyond the free stateposition when the valve is opened. Thus, the pin of such prior artvalves always stays out of contact with the flanks of the groove wall asthe valve is opened except when the valve sticks to the seat.

The alternate tension-compression states of the bellows of thisinvention increases bellows life since the extension and compressionstrokes are reduced in magnitude as compared to the compression strokeof the prior art valves noted above.

The 20 80 tension-compression stroke ratio is characteristic of thepreferred embodiment. Other ratios should be considered within thespirit of the invention.

This invention was designed to be incorporated into a large capacityvalve having ratings similar to smaller valves. The preferred embodimentcan handle 2,500 p.s.i. at 650 F. with a maximum temperature range fromcryogenic to 1,500 F.

Because of the much larger capacity of the valve, the range ofapplication is much wider than smaller models. Its wide ranges oftemperature and pressure capabilities make it a wise choice forcryogenic fluids as well as hot oil, chemicals and steam lines. Theextra reliability of the bellows seal principle makes it the safestchoice for systems where even very small system fluid leakage could bedangerous or expensive. The bellows seal eliminates all packings,O-rings, and other sliding seals. There is zero leakage to atmosphere.In systems which are very sensitive to moisture it does away withatmospheric contamination. There is also a secondary system to preventleakage inthe unlikely event of a bellows failure.

The inverted bellows (wherein system fluid acts on the external surfaceof the bellows rather than the bellows interior) allows much more rapidheat transfer in systems where the valve body must be heated to keep thesystem fluid hot. The inverted bellows also increases bellows life inthe larger size valve. It helps in rapid evacuation of the bellows forultra-high vacuum service, and makes cleaning the valve simplier.

The valve of this invention may be operated by means of a remoteoperator in lieu of handle 20. As an example a double acting aircylinder or a normally closed air cylinder may be used. Air operatedbellows valves provide for remote control of tough-to-handle fluidsystems such as nuclear fueled power generating plants.

What is claimed:

1. A valve comprising in combination:

a body having a bore, an inlet and an outlet, a fluid passagewayinterconnecting said inlet, outlet and said bore, and an annular sealingseat in said passageway substantially coaxial with said bore;

a bonnet connected to said body and having a central passage alignedsubstantially coaxial with said bore;

an actuator projecting through said central passage;

a stem connected to said actuator, the lower end of said stem projectinginto said bore and including sealing means to engage said seat, saidstem adapted to be moved into and out of engagement with said seat uponmovement of said actuator;

a bellows surrounding a portion of said stem, the lower end of saidbellows being bonded to said stem with the upper end being bonded toweld ring means, the bond between said bellows and said weld ring meanscomprising weld means substantially at the periphery of said bellows;

concentric circumferential grooves in said weld ring means with at leastone of said grooves opening upwardly toward a flat face on the lower endof said bonnet, said upwardly opening groove retaining a sealing O-ringcompressed between said flat face and the walls of said upwardly openinggroove;

another of said grooves being sufficiently close to an edge of said ringmeans as to form a projecting flange of radial thickness notsubstantially greater than the thickness of said bellows, said bellowsperiphery being welded to said flange substantially at its crest;

said weld ring means being clamped between the valve body near the upperterminus of said bore and said bonnet near the lower terminus of saidcentral passage, the internal diameter of said central passage beingless than the internal diameter of said bore;

a relieved surface adjacent said ring means merging with one of (a) saidpassage lower terminus or (b) said bore upper terminus;

the maximum diameter of said relieved surface being greater than thediameter of the crest of the flange welded to said bellows;

sealing means between said valve body and said weld ring means.

2. The invention of claim 1 in which said sealing means comprises asealing ring interposed between said valve body and said weld ringmeans.

3. The invention of claim 1 in which said relieved surface is anoutwardly flared surface defined on said bonnet and said flange of saidweld ring means is defined substantially adjacent the inner surface ofsaid weld ring means with said bellows upper end welded to said flangein substantially a vertical position.

4. The invention of claim 1 in which said relieved surface is anoutwardly flared surface defined on said valve body and said flange ofsaid weld ring means is defined at the bottom most surface of said weldring means with said upper end of said bellows welded to said flange insubstantially a horizontal position.

' 5. The invention of claim 1 in which the width of the crest of theflange of said weld ring means is not substantially less than two timesnor substantially greater than three and one-half times the thickness ofsaid bellows.

6. The invention of claim 1 in which said sealing means comprises a weldbead at the external surface of said valve body and said weld ringmeans.

7. The invention of claim 6 in which a cooperating rise and recess aredefined in said body and said weld ring means.

8. A valve comprising in combination:

a body having a bore, an inlet and an outlet, a fluid passagewayinterconnecting said inlet, outlet and said bore, and an annular sealingseat in said passageway substantially coaxial with said bore;

a bonnet connected to said body and having a central passage alignedsubstantially coaxial with said bore;

an actuator projecting through said central passage and beingselectively rotatable in said passage;

a substantially non-rotatable stem having a lower end projecting intosaid bore and including sealing means to engage said seat, said stemadapted to be moved along said bore into and out of engagement with saidseat responsive to rotational movement of said actuator;

connection means between said stem and said actuator;

said connection means comprising a cup-shaped portion on one of saidactuator and said stem and a projecting end on the other of saidactuator and said stem with opposed semicircular shaped grooves definedin both said cup-shaped portion and said projecting end;

a pair of detent means projecting from said cupshaped portion and intosaid opposed grooves for locking said stem and said actuator togetherwhile allowing relative rotational movement therebetween;

the opposed faces of said cup-shaped portion and said projecting endhaving a concave, substantially cone-shaped surface for engaging afriction reducing ball held therebetween to minimize the: amount oftorque transmitted from said actuator to said stem during rotation ofsaid actuator to effect movement of said stem into and out of engagementwith said seat.

9. The invention of claim 8 in which said detents are positionedsubstantially 180 apart in order to impart balanced thrust forces tosaid stem from said actuator.

10. The invention of claim 8 in which the diameter of the semicirculargroove in said stem is greater than the diameter of said detents.

11. A valve comprising in combination:

a body portion having a bore, an inlet and an outlet,

a fluid passageway interconnecting said inlet, outlet and said bore, andan annular sealing seat in said passageway substantially coaxial withsaid bore;

a bonnet connected to said body and having a central passage alignedsubstantially coaxial with said bore;

an actuator projecting through said central passage in threadedengagement with said bonnet;

secondary seal means at said actuator and said bonnet and positionedabove the threads of said actuator and said bonnet;

a substantially non-rotatable stem, the lower end of said stemprojecting into said bore and including sealing means to engage saidseat, said stem adapted to be moved into and out of engagement with saidseat in response to rotation of said actuator in said threadedengagement;

a bellows surrounding a portion of said stem, the lower end of saidbellows being bonded to said stem with the upper end being bonded toring means;

said ring means being clamped between said valve body and said bonnet;

connection means between said actuator and said stem for locking saidactuator and said stem together while allowing for relative rotationalmovement therebetween, said connection means being positioned above saidring means;

an externally projecting shoulder extending from said actuator andpositioned above said connection means, a complementary internallyextending shoulder defined on said bonnet, said shoulders togetherdefining a back seat seal.

12. The invention of claim 11 in which the sealing means of said stemcomprises a tip connected to the stem end, said tip including apolygonal body coaxially aligned with said stem, said polygonal bodyhaving a plurality of guiding comers for engaging the bore wall of saidbody, the lower end of said polygonal body including a cavity openingtoward said annular sealing seat, and a plug disposed in said cavity.

13. The invention of claim 11 wherein the interengaging threads of saidactuator and said bonnet serve to reciprocate the stem between open andclosed positions, the ratio of the axial length of the threads to threaddiameter being not substantially less than 1.5.

14. The invention of claim 11 in which at least one port is defined insaid bonnet between said back seat seal and the interengaging threads ofsaid actuator and said bonnet.

15. The invention of claim 11 in which said connection means is definedas a cup-shaped member on either one of said actuator or said stem and aprojecting end on the other of said actuator or said stem with theopposed faces of said cup-shaped member and said projecting end eachhaving a concave, substantially cone-shaped surface for abutting afriction reducing ball held therebetween to minimize the amount oftorque transmitted from the rotatable actuator to the verticallyreciprocatable stem.

16. The invention of claim 15 in which the externally projectingshoulder of said actuator is defined by the upper surface of saidcup-shaped portion.-

17. The invention of claim 15 in which opposed semicircular shapedgrooves are defined in said cup-shaped portion and said projecting endand a pair of detent means project from the wall of said cup-shapedportion into said grooves for locking the stem and actuator to- I 21.The invention of claim 20 in which the bellows in the valve closedposition is extended 20 percent beyond the free state bellows position,and the bellows in the valve opened position is compressed 80 percentbeyond the free state bellows position.

22. A valve comprising in combination: a body having a bore, an inletand an outlet, a fluid passageway interconnecting said inlet, outlet andsaid bore, and an annular sealing seat in said passageway substantiallycoaxial with said bore;

a substantially non-rotatable stem, the lower end of said stemprojecting into said bore and including sealing means to engage saidseat, said stem adapted to be selectively longitudinally moved withinsaid bore into and out of sealing engagement with said seat;

-a bellows surrounding a portion of said stem, said bellows having oneend bonded to seal means at said stem and the other end bonded to sealmeans at said body;

said sealing means of said stem comprising a tip connected to the stemend, said tip including a polygonal body coaxially aligned with saidstem, said polygonal body having a plurality of guiding corners forengaging the bore wall of said body, the lower end of said polygonalbody including a cavity opening toward said annular sealing seat, and aplug disposed in said cavity.

1. A valve comprising in combination: a body having a bore, an inlet andan outlet, a fluid passageway interconnecting said inlet, outlet andsaid bore, and an annular sealing seat in said passageway substantiallycoaxial with said bore; a bonnet connected to said body and having acentral passage aligned substantially coaxial with said bore; anactuator projecting through said central passage; a stem connected tosaid actuator, the lower end of said stem projecting into said bore andincluding sealing means to engage said seat, said stem adapted to bemoved into and out of engagement with said seat upon movement of saidactuator; a bellows surrounding a portion of said stem, the lower end ofsaid bellows being bonded to said stem with the upper end being bondedto weld ring means, the bond between said bellows and said weld ringmeans comprising weld means substantially at the periphery of saidbellows; concentric circumferential grooves in said weld ring means withat least one of said grooves opening upwardly toward a flat face on thelower end of said bonnet, said upwardly openIng groove retaining asealing O-ring compressed between said flat face and the walls of saidupwardly opening groove; another of said grooves being sufficientlyclose to an edge of said ring means as to form a projecting flange ofradial thickness not substantially greater than the thickness of saidbellows, said bellows periphery being welded to said flangesubstantially at its crest; said weld ring means being clamped betweenthe valve body near the upper terminus of said bore and said bonnet nearthe lower terminus of said central passage, the internal diameter ofsaid central passage being less than the internal diameter of said bore;a relieved surface adjacent said ring means merging with one of (a) saidpassage lower terminus or (b) said bore upper terminus; the maximumdiameter of said relieved surface being greater than the diameter of thecrest of the flange welded to said bellows; sealing means between saidvalve body and said weld ring means.
 2. The invention of claim 1 inwhich said sealing means comprises a sealing ring interposed betweensaid valve body and said weld ring means.
 3. The invention of claim 1 inwhich said relieved surface is an outwardly flared surface defined onsaid bonnet and said flange of said weld ring means is definedsubstantially adjacent the inner surface of said weld ring means withsaid bellows upper end welded to said flange in substantially a verticalposition.
 4. The invention of claim 1 in which said relieved surface isan outwardly flared surface defined on said valve body and said flangeof said weld ring means is defined at the bottom most surface of saidweld ring means with said upper end of said bellows welded to saidflange in substantially a horizontal position.
 5. The invention of claim1 in which the width of the crest of the flange of said weld ring meansis not substantially less than two times nor substantially greater thanthree and one-half times the thickness of said bellows.
 6. The inventionof claim 1 in which said sealing means comprises a weld bead at theexternal surface of said valve body and said weld ring means.
 7. Theinvention of claim 6 in which a cooperating rise and recess are definedin said body and said weld ring means.
 8. A valve comprising incombination: a body having a bore, an inlet and an outlet, a fluidpassageway interconnecting said inlet, outlet and said bore, and anannular sealing seat in said passageway substantially coaxial with saidbore; a bonnet connected to said body and having a central passagealigned substantially coaxial with said bore; an actuator projectingthrough said central passage and being selectively rotatable in saidpassage; a substantially non-rotatable stem having a lower endprojecting into said bore and including sealing means to engage saidseat, said stem adapted to be moved along said bore into and out ofengagement with said seat responsive to rotational movement of saidactuator; connection means between said stem and said actuator; saidconnection means comprising a cup-shaped portion on one of said actuatorand said stem and a projecting end on the other of said actuator andsaid stem with opposed semicircular shaped grooves defined in both saidcup-shaped portion and said projecting end; a pair of detent meansprojecting from said cup-shaped portion and into said opposed groovesfor locking said stem and said actuator together while allowing relativerotational movement therebetween; the opposed faces of said cup-shapedportion and said projecting end having a concave, substantiallycone-shaped surface for engaging a friction reducing ball heldtherebetween to minimize the amount of torque transmitted from saidactuator to said stem during rotation of said actuator to effectmovement of said stem into and out of engagement with said seat.
 9. Theinvention of claim 8 in which said detents are positioned substantially180* apart in order to impart balanceD thrust forces to said stem fromsaid actuator.
 10. The invention of claim 8 in which the diameter of thesemicircular groove in said stem is greater than the diameter of saiddetents.
 11. A valve comprising in combination: a body portion having abore, an inlet and an outlet, a fluid passageway interconnecting saidinlet, outlet and said bore, and an annular sealing seat in saidpassageway substantially coaxial with said bore; a bonnet connected tosaid body and having a central passage aligned substantially coaxialwith said bore; an actuator projecting through said central passage inthreaded engagement with said bonnet; secondary seal means at saidactuator and said bonnet and positioned above the threads of saidactuator and said bonnet; a substantially non-rotatable stem, the lowerend of said stem projecting into said bore and including sealing meansto engage said seat, said stem adapted to be moved into and out ofengagement with said seat in response to rotation of said actuator insaid threaded engagement; a bellows surrounding a portion of said stem,the lower end of said bellows being bonded to said stem with the upperend being bonded to ring means; said ring means being clamped betweensaid valve body and said bonnet; connection means between said actuatorand said stem for locking said actuator and said stem together whileallowing for relative rotational movement therebetween, said connectionmeans being positioned above said ring means; an externally projectingshoulder extending from said actuator and positioned above saidconnection means, a complementary internally extending shoulder definedon said bonnet, said shoulders together defining a back seat seal. 12.The invention of claim 11 in which the sealing means of said stemcomprises a tip connected to the stem end, said tip including apolygonal body coaxially aligned with said stem, said polygonal bodyhaving a plurality of guiding corners for engaging the bore wall of saidbody, the lower end of said polygonal body including a cavity openingtoward said annular sealing seat, and a plug disposed in said cavity.13. The invention of claim 11 wherein the interengaging threads of saidactuator and said bonnet serve to reciprocate the stem between open andclosed positions, the ratio of the axial length of the threads to threaddiameter being not substantially less than 1.5.
 14. The invention ofclaim 11 in which at least one port is defined in said bonnet betweensaid back seat seal and the interengaging threads of said actuator andsaid bonnet.
 15. The invention of claim 11 in which said connectionmeans is defined as a cup-shaped member on either one of said actuatoror said stem and a projecting end on the other of said actuator or saidstem with the opposed faces of said cup-shaped member and saidprojecting end each having a concave, substantially cone-shaped surfacefor abutting a friction reducing ball held therebetween to minimize theamount of torque transmitted from the rotatable actuator to thevertically reciprocatable stem.
 16. The invention of claim 15 in whichthe externally projecting shoulder of said actuator is defined by theupper surface of said cup-shaped portion.
 17. The invention of claim 15in which opposed semi-circular shaped grooves are defined in saidcup-shaped portion and said projecting end and a pair of detent meansproject from the wall of said cup-shaped portion into said grooves forlocking the stem and actuator together while allowing relativerotational movement.
 18. The invention of claim 17 in which the detentmeans are spaced 180* apart so as to transmit balanced thrust forces tosaid stem from said actuator.
 19. The invention of claim 17 in which thediameter of the groove in said stem is larger than the diameter of saiddetent means.
 20. The invention of claim 11 in which the operatingstroke of the stem from the fully closed position to the fully openedposition moves tHe bellows from a state of extension to a state ofcompression.
 21. The invention of claim 20 in which the bellows in thevalve closed position is extended 20 percent beyond the free statebellows position, and the bellows in the valve opened position iscompressed 80 percent beyond the free state bellows position.
 22. Avalve comprising in combination: a body having a bore, an inlet and anoutlet, a fluid passageway interconnecting said inlet, outlet and saidbore, and an annular sealing seat in said passageway substantiallycoaxial with said bore; a substantially non-rotatable stem, the lowerend of said stem projecting into said bore and including sealing meansto engage said seat, said stem adapted to be selectively longitudinallymoved within said bore into and out of sealing engagement with saidseat; a bellows surrounding a portion of said stem, said bellows havingone end bonded to seal means at said stem and the other end bonded toseal means at said body; said sealing means of said stem comprising atip connected to the stem end, said tip including a polygonal bodycoaxially aligned with said stem, said polygonal body having a pluralityof guiding corners for engaging the bore wall of said body, the lowerend of said polygonal body including a cavity opening toward saidannular sealing seat, and a plug disposed in said cavity.